This invention relates to printing presses of the lithographic type and particularly to a zone controlled dampening means for such presses.
The prior art discloses various systems for depositing a dampening solution onto the oscillating roller of the printing press.
U.S. Pat. No. 176,193 to F. Rhell discloses a conventional dampening apparatus for lithographic presses using a water pan, pan roller and ductor roller to transfer water to the vibrator. U.S. Pat. Nos. 1,719,017 and 1,798,850 to S. Moe et al basically disclose spraying systems wherein moisture is directed onto the plate cylinder. Schultz U.S. Pat. No. 1,812,720 discloses a system using capillary action to wet a pan roller with moving belts. The system includes a conventional ductor roller to transfer water to the vibrator. Later Schultz U.S. Pat. No. 1,991,962 adds spray heads and needle valves to essentially the same system.
Stevens U.S. Pat. No. 2,231,694 uses a series of small pumps to deliver water through nozzles or needle valves but the system fails to achieve even distribution. On the other hand, Rogers U.S. Pat. No. 2,733,654 is directed to a conventional dampening arrangement wherein ink and water are applied to a form roller simultaneously using a pan roller and a ductor. The Rogers system does not eliminate variables between the ductor, pan roller and the distributor. U.S. Pat. No. 3,504,626 to E. W. Worthington discloses a conventional pan roller arrangement.
A further view of the prior art is shown illustrated in U.S. Pat. No. 2,183,568 to W. F. Huck wherein a perforated cylinder covered with an absorbent felt is fed water internally by a series of tubes. Smith U.S. Pat. No. 3,651,756 utilizes a spraying system employing a series of spray heads for applying water directly to the ink rollers and Klinger U.S. Pat. No. 3,924,531 uses spray heads or slingers to apply water directly onto the ink rollers.
In contrast to the prior art cited above, the present invention pertains to a unique zone controlled dampening system for regulating the flow of dampening solution onto the oscillating roller. The system includes a plurality of means longitudinally spaced along the oscillating roller, each independently controllable allowing more or less dampening solution onto the oscillating roller and without any of the disadvantages of the above cited prior art.